Emissions control
AssigneeJohnson Matthey Public Limited Company
InventorsGuy Richard Chandler, Martyn Vincent Twigg
Life of this patent
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Abstract
A cost-effective solution to remove particulates from diesel, especially light-duty diesel engines incorporates an oxidation catalyst (2) effective to convert NO in the exhaust from the engine to NO2 and a particulate trap (4) which traps no more than 85% by weight of the particulate, optionally by permitting gas to by-pass the trap.
Claims14
An emission control exhaust gas aftertreatment apparatus for exhaust gases from diesel engines comprising a source of additional NO2 and a particulate filter, which particulate filter comprises:
- a filter medium having sufficient capacity to accumulate particulates on the filter medium under all normal operating conditions,
- wherein said particulate filter is configured to trap no more than 85 wt % of engine-out particulates in the exhaust gas on said filter medium for combustion in the presence of said NO2 in said particulate filter,
- wherein a portion of exhaust gases do not pass across said filter medium, and
- wherein the filter is configured to cause exhaust gases to continuously flow into the particulate filter during operation and the resulting exhaust gases to be passed to atmosphere.
A method of controlling emissions from diesel engine exhaust gases by trapping and subsequently combusting particulate matter, comprising:
- passing exhaust gases through a particulate filter configured to trap no more than 85 wt % of the particulate matter in the exhaust gases on a filter medium of the particulate filter, wherein a portion of the exhaust gases do not pass across the filter medium;
- and
- combusting said trapped particulate matter in the presence of NO2 from a source of additional NO2,
- wherein the exhaust gases continuously flow into the particulate filter during operation and the resulting exhaust gases are passed to atmosphere.
An emission control exhaust gas aftertreatment apparatus for exhaust gases from diesel engines comprising a source of additional NO2 and a particulate filter having a filter medium with a sufficient capacity to accumulate particulate under all normal operating conditions, wherein said filter medium is effective to trap no more than 85 wt % of engine-out particulates for combustion in the presence of said NO2.
A method of controlling emissions from diesel engine exhaust gases by trapping and subsequently combusting particulate matter, comprising:
- trapping no more than 85 wt % of said particulate matter in said exhaust in a filter medium of a particulate filter by passing said exhaust gases across said filter medium, wherein said filter medium has sufficient capacity to accumulate particulate under all normal operating conditions in an amount of no more than 85 wt % of engine-out particulates;
- and
- combusting said trapped particulate matter in the presence of NO2 from a source of additional NO2.
Dependencies are inferred from the claim text.